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tools/openfst-1.6.7/src/include/fst/script/print-impl.h
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// See www.openfst.org for extensive documentation on this weighted
// finite-state transducer library.
//
// Stand-alone class to print out binary FSTs in the AT&T format, a helper
// class for fstprint.cc.
#ifndef FST_SCRIPT_PRINT_IMPL_H_
#define FST_SCRIPT_PRINT_IMPL_H_
#include <ostream>
#include <sstream>
#include <string>
#include <fst/fstlib.h>
#include <fst/util.h>
DECLARE_string(fst_field_separator);
namespace fst {
// Print a binary FST in textual format (helper class for fstprint.cc).
// WARNING: Stand-alone use of this class not recommended, most code should
// read/write using the binary format which is much more efficient.
template <class Arc>
class FstPrinter {
public:
using StateId = typename Arc::StateId;
using Label = typename Arc::Label;
using Weight = typename Arc::Weight;
FstPrinter(const Fst<Arc> &fst, const SymbolTable *isyms,
const SymbolTable *osyms, const SymbolTable *ssyms, bool accep,
bool show_weight_one, const string &field_separator,
const string &missing_symbol = "")
: fst_(fst),
isyms_(isyms),
osyms_(osyms),
ssyms_(ssyms),
accep_(accep && fst.Properties(kAcceptor, true)),
ostrm_(nullptr),
show_weight_one_(show_weight_one),
sep_(field_separator),
missing_symbol_(missing_symbol) {}
// Prints FST to an output stream.
void Print(std::ostream *ostrm, const string &dest) {
ostrm_ = ostrm;
dest_ = dest;
const auto start = fst_.Start();
if (start == kNoStateId) return;
// Initial state first.
PrintState(start);
for (StateIterator<Fst<Arc>> siter(fst_); !siter.Done(); siter.Next()) {
const auto s = siter.Value();
if (s != start) PrintState(s);
}
}
private:
void PrintId(StateId id, const SymbolTable *syms, const char *name) const {
if (syms) {
string symbol = syms->Find(id);
if (symbol.empty()) {
if (missing_symbol_.empty()) {
FSTERROR() << "FstPrinter: Integer " << id
<< " is not mapped to any textual symbol"
<< ", symbol table = " << syms->Name()
<< ", destination = " << dest_;
symbol = "?";
} else {
symbol = missing_symbol_;
}
}
*ostrm_ << symbol;
} else {
*ostrm_ << id;
}
}
void PrintStateId(StateId s) const { PrintId(s, ssyms_, "state ID"); }
void PrintILabel(Label l) const { PrintId(l, isyms_, "arc input label"); }
void PrintOLabel(Label l) const { PrintId(l, osyms_, "arc output label"); }
void PrintState(StateId s) const {
bool output = false;
for (ArcIterator<Fst<Arc>> aiter(fst_, s); !aiter.Done(); aiter.Next()) {
const auto &arc = aiter.Value();
PrintStateId(s);
*ostrm_ << sep_;
PrintStateId(arc.nextstate);
*ostrm_ << sep_;
PrintILabel(arc.ilabel);
if (!accep_) {
*ostrm_ << sep_;
PrintOLabel(arc.olabel);
}
if (show_weight_one_ || arc.weight != Weight::One())
*ostrm_ << sep_ << arc.weight;
*ostrm_ << "
";
output = true;
}
const auto weight = fst_.Final(s);
if (weight != Weight::Zero() || !output) {
PrintStateId(s);
if (show_weight_one_ || weight != Weight::One()) {
*ostrm_ << sep_ << weight;
}
*ostrm_ << "
";
}
}
const Fst<Arc> &fst_;
const SymbolTable *isyms_; // ilabel symbol table.
const SymbolTable *osyms_; // olabel symbol table.
const SymbolTable *ssyms_; // slabel symbol table.
bool accep_; // Print as acceptor when possible?
std::ostream *ostrm_; // Text FST destination.
string dest_; // Text FST destination name.
bool show_weight_one_; // Print weights equal to Weight::One()?
string sep_; // Separator character between fields.
string missing_symbol_; // Symbol to print when lookup fails (default
// "" means raise error).
//
FstPrinter(const FstPrinter &) = delete;
FstPrinter &operator=(const FstPrinter &) = delete;
};
} // namespace fst
#endif // FST_SCRIPT_PRINT_IMPL_H_
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